The prior art shows installations of this kind in which the conveyor devices provided are conveyor tracks on which balancers are adapted to travel, the individual workpiece holders being transported by these balancers through the first set of polishing machines and to the re-clamping table. At each individual working station the workpiece holder is inserted by hand into the polishing machine or is filled with unpolished pieces of cutlery on the clamping device. In this known installation, although the operators no longer need to transfer the workpiece holders containing the pieces of cutlery from machine to machine, nevertheless, as previously, they must insert them individually by hand into the machines and place them individually by hand on the re-clamping device and clamping or unclamping device. Furthermore, it has been found that the conveyor tracks with their balancers impair the accessibility of the individual machines.
From the periodical "Galvanotechnik" 1958, No. 9, page 755, an automatic installation for polishing pieces of cutlery is known in which the polishing machines are disposed along a continuous rectilinear conveyor track which permits the use of only two workpiece holders, since these must be returned on the same track if transfer by hand is excluded. The two workpiece holders travel between the clamping device and the re-clamping device on the one hand, and between the re-clamping device and the unclamping device on the other hand. The workpiece holders are moved on plates rectilinearly along the main conveyor track in the manner described. These plates together with the workpiece holders are in each case fed at right-angles to the main transport track and horizontally by means of pneumatic driving cylinders to the individual polishing machines. Apart from the low capacity of this installation, the individual polishing machines are practically inaccessible from the front, that is to say from the side from which the workpiece holders are fed, so that the changing of the polishing rollers, which is necessary every day, and the frequent changing-over to different kinds of cutlery, which is often necessary, particularly in smaller plants, are difficult to effect.
From the periodical "Metalloberflache" l967, No. 2, pages 45 to 48, so-called automatic circular table machines are known for the grinding and polishing of metal workpieces, in which the workpieces are disposed on a table adapted to be driven in timed sequence by equal angular steps and are fed to the individual grinding stations by corresponding timed rotation of the table. Here again the individual grinding devices are inaccessible or accessible only with difficulty from the front, that is to say the side on which the rotatable table is disposed.